This invention relates to improvements in wheels for machines which normally require wide faced tyres for the purpose of spreading the load carried over grass covered ground or other soft surfaces, for example, golf greens. In particular, the invention relates to improvements in wheels for use on golf carts and grass mowing machines.
The wheels used on such golf carts and grass mowing machines usually have a conventional pneumatic tyre and the overall diameter of the wheel and tyre is approximately eighteen (18) inches, the tyre having a curved ground engaging surface of approximately eight (8) inches in width. The width of the tyre is necessarily restricted since the wider the tyre is, then the greater is the scourging effect on the ground when the wheel is turning. The scourging of the ground is caused by the wheel when turning as the outer part of the wheel must effectively rotate faster than the inner part, since the former has in effect to travel a greater distance. Since the outer part of the wheel cannot rotate faster than the inner part, the wheel skids and this skidding scourges the ground surface. However, even a wheel having a width of eight (8) inches substantially scourges the ground when turning. This is particularly the case on golf fairways.
The scourging of the ground is accentuated by the weight which the wheel carries and which is exerted on the ground surface.
Golf carts are generally used to carry two golf players and two golf bags with clubs, and have a gross weight including players, bags and clubs of approximately one thousand two hundred pounds (1200 lbs). The golf carts usually have four wheels with pneumatic tyres. Due to the rounded face of the tyres the combined weight carried by the wheels is spread over a weight bearing area of only sixteen (16) square inches per wheel. This represents an area of the ground engaging surface of each tyre, which actually contacts the ground surface at any instant, of only four (4) inches wide and four (4) inches in the direction of travel. Thus, for a four-wheeled golf cart of a combined weight of one thousand two hundred pounds (1200 lbs) this represents approximately nineteen (19) pounds per square inch (19 p.s.i.) of pressure on the ground surface. This pressure damages the ground surface and aggravates the scourging effect when the wheels are turning. The main disadvantages of using existing wheels for golf carts and grass mowing machines are:
1. The daily use of such heavy machines on fairways and greens causes damage to the grass covered ground surface, particularly when turning. PA1 2. In wet or saturated ground conditions golf course management are often compelled to close the course, thereby causing serious financial loss to the club. PA1 3. Due to the foregoing two disadvantages some clubs are reluctantly forced to build cement paths over large sections of the course. These paths are to the disadvantage of the players, are considered ugly, and in affect the run of play as the players cannot directly follow the direction in which the ball has been played and thus the game is considerably slowed down.